The use of ink-jet printers to form images such as alpha-numeric characters and graphics on absorbent media such as paper is well-known.
However, the use of the same inks on transparent media, such as polyester films, commonly known as Mylar, has not produced the same high optical density of print, which results in intense colors, obtained with inherently absorbent media. As is currently available, such non-absorbing media, even when an "ink-receptive" coating is applied, suffer from inherently long drying times, moisture sensitivity, non-homogeneous area fill, and low optical densities.
Attempts have been made to remedy the situation in which ink-jet transparencies are slow to dry or lack capacity to absorb sufficient volumes of ink, with a goal of approaching performance obtained with highly absorbent media. One such attempt is described in a technical paper by D. R. Titterington et al, "Development of a Transparent Receiving Sheet for Ink-Jet Printing", Journal of Imaging Science, Vol. 30, No. 1, pp. 4-8 (Jan/Feb 1986). This paper describes the use of certain transparent hydrophilic coatings to permit the use of aqueous-based inks for printing on transparent media. However, this reference addresses the problem of slow drying transparencies and does not disclose ways to improve image quality.
While such coatings are useful, considerable work remains to be done to develop suitable inks and methods of application that permit substantially uniform high color density images to be produced on transparent, non-absorbing media approaching that which can be produced on absorbing media such as paper.